CN108725258B - Automobile anti-lock state detection method and detection system for electric automobile - Google Patents

Abstract

The invention discloses an automobile anti-lock state detection method for an electric automobile, which comprises the following steps of: to electric motorThe original rotating speed of the motor of the automobile is collected to generate an original rotating speed signal V of the motor ₁ The method comprises the steps of carrying out a first treatment on the surface of the For the original rotating speed signal V of the motor ₁ Smoothing filter processing is carried out to generate a motor rotating speed smoothing filter signal V ₂ The method comprises the steps of carrying out a first treatment on the surface of the Calculating an original rotating speed signal V of the motor ₁ And motor rotation speed smoothing filter signal V ₂ The difference value delta V is used as a motor rotation speed fluctuation value; outputting a motor rotation speed fluctuation value every time at a certain interval, comparing the motor rotation speed fluctuation value output every time with a set threshold value, judging that the electric automobile enters a locking state if the motor rotation speed fluctuation values of a plurality of continuous interval periods X are all larger than the set threshold value, performing anti-lock braking control by a motor controller of the electric automobile, and exiting braking energy recovery control. The invention also discloses a detection system for realizing the detection method of the anti-lock state of the automobile for the electric automobile.

Description

A vehicle anti-lock braking state detection method and detection system for an electric vehicle

technical field

The invention relates to the field of electric vehicle control, in particular to a method for detecting an anti-lock braking state of an electric vehicle and a detection system thereof.

Background technique

The Antilock Brake System is one of the automotive braking systems, which can effectively prevent the car wheels from slipping during the braking process and improve the stability and control performance of the automotive braking system. .

Compared with traditional internal combustion locomotives, electric vehicles can convert part of the kinetic energy recovered during braking into electrical energy and store them for driving, saving energy and improving cruising range, making electric vehicles more competitive. However, when the anti-lock braking system of the electric vehicle is working, in order to ensure the stability of the electric vehicle, energy recovery needs to be disabled.

In order to realize the above two functions, it is necessary to accurately detect whether the current electric vehicle is in a locked state. At present, the above-mentioned detection purpose is generally realized by means of ABS sending through the bus. When some ABS do not have the ability to send out whether the electric vehicle is in a locked state through the bus but not limited to the bus, because the energy recovery cannot be prohibited when the electric vehicle is in the locked state, the electric vehicle cannot perform energy recovery in any state. Recycle.

On the basis of the above research, the applicant has conducted useful explorations and attempts, and has found a solution to the above problems. The technical solutions to be introduced below are produced under this background.

Contents of the invention

One of the technical problems to be solved by the present invention is to provide a method for detecting the anti-lock braking state of an electric vehicle in view of the deficiencies in the prior art. When the function is in the dead state, the electric vehicle still has the energy recovery function, which increases the safety and stability of the electric vehicle.

The second technical problem to be solved by the present invention is to provide a detection system for realizing the detection method of the vehicle anti-lock brake state for electric vehicles.

As a first aspect of the present invention, a method for detecting an anti-lock braking state of an electric vehicle comprises the following steps:

Collect the original motor speed of the electric vehicle, calculate and process the collected motor original speed, and generate a motor original speed signal V ₁ ;

Perform smoothing and filtering processing on the generated original motor speed signal _V1 to generate a motor speed smoothing and filtering signal _V2 ;

Calculate the difference ΔV=V ₁ -V ₂ between the original motor speed signal V ₁ and the motor speed smoothing filter signal V ₂ , and use the difference ΔV as the motor speed fluctuation value;

The motor speed fluctuation value is output once at a certain time interval T, and the motor speed fluctuation value output each time is compared with the set threshold value M. If the motor speed fluctuation values of multiple consecutive interval periods X are greater than the set threshold value M, then When it is determined that the electric vehicle enters the locked state, the motor controller of the electric vehicle performs anti-lock braking control and exits braking energy recovery control at the same time.

In a preferred embodiment of the present invention, a second-order filter is used to perform smoothing and filtering on the generated original motor speed signal V ₁ .

In a preferred embodiment of the present invention, the transfer function of the second-order filter is:

Wherein, the value range of a is 0.7-1, the value range of b is 5.5-6.6, the value range of c is 1.5-2.5, and the value range of d is 4.5-5.

In a preferred embodiment of the present invention, the values of a, b, c, and d in the transfer function of the second-order filter are 1, 6, 2, and 5, respectively.

In a preferred embodiment of the present invention, the set threshold M is 100rpm-200rpm.

In a preferred embodiment of the present invention, the interval time T for outputting the motor speed fluctuation value is 0.5ms˜1.5ms.

In a preferred embodiment of the present invention, the number of consecutive intervals is 15-25.

As a second aspect of the present invention, a detection system for realizing the detection method of the above-mentioned vehicle anti-lock braking state for an electric vehicle includes:

A motor speed sensor installed in the electric motor of the electric vehicle for collecting the original speed of the motor, the motor speed sensor converts the collected original speed of the motor into an electrical signal of the motor speed for output;

A motor main controller, the motor main controller includes a motor speed calculation module, a motor speed smoothing filter module, a locked state judgment module and a motor control module;

The motor speed calculation module has a motor speed signal input end and a motor speed signal output end, and the motor speed signal input end of the motor speed calculation module is connected to the signal output end of the motor speed sensor for receiving the The motor speed electrical signal output by the motor speed sensor, and the received motor speed electrical signal is calculated and processed, and the original motor speed signal _V1 is generated for output;

The motor speed smoothing filter module has a motor speed smoothing filter input end and a motor speed smoothing filter output end, the motor speed smoothing filter input end of the motor speed smoothing filter module is connected with the motor speed signal output of the motor speed calculation module terminal connection, for receiving the motor original speed signal V ₁ output by the motor speed calculation module, and performing smoothing and filtering processing on the received motor original speed signal V ₁ to generate a motor speed smoothing and filtering signal V ₂ for output;

The locked state judging module has a motor original speed signal input end, a motor speed smoothing filter signal input end and a locked state signal output end, the motor original speed signal input end and the motor speed of the locked state judging module The smoothing filter signal input end is respectively connected with the motor speed signal output end of the motor speed calculation module and the motor speed smoothing filter output end of the motor speed smoothing filter module, and is used to receive the original motor speed output by the motor speed calculation module signal V ₁ and the motor speed smoothing filter signal V ₂ output by the motor speed smoothing filter module, and calculate the difference between the original motor speed signal V ₁ and the motor speed smoothing filter signal V ₂ ΔV=V ₁ -V ₂ , The difference ΔV is used as the motor speed fluctuation value, and then the motor speed fluctuation value is compared with the set threshold value. If the motor speed fluctuation values of multiple consecutive intervals are greater than the set threshold value, it is determined that the electric vehicle enters a locked state. The locking state judging module outputs the locking state signal through the locking state signal output terminal;

The motor control module has a locking state signal output end and a motor control signal output end, the locking state signal output end of the motor control module is connected to the locking state signal output end of the locking state judging module, Its motor control signal output terminal is connected with the electric motor of the electric vehicle, and after the motor control module receives the locked state signal output by the locked state judging module, it performs anti-lock braking control on the electric motor of the electric vehicle, At the same time, the braking energy recovery control is exited.

Owing to adopting above technical scheme, the beneficial effect of the present invention is:

1. When the ABS in the electric vehicle does not have the function of sending out the locked state, the electric vehicle can still have the function of energy recovery.

2. It is convenient, direct and highly reliable to judge whether the car is in a locked state through the motor speed.

3. The filter algorithm based on the second-order filter is used to smooth and filter the original speed of the motor, which has the advantage of fast response speed and has a good filtering effect on the motor speed in the locked state. At the same time, according to different vehicle types, the best filtering effect can be obtained by calibrating the parameters a, b, c, and d of the second-order filter.

4. According to different types of electric vehicles, it is possible to accurately determine whether the electric vehicle is currently in a locked state by calibrating the threshold M, sampling time T and continuous interval period X, so as to quickly adopt anti-lock braking control and exit braking energy recovery at the same time , increase the security and stability of the system.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is a schematic flow chart of the method for detecting the anti-lock braking state of an electric vehicle according to the present invention.

Fig. 2 is a structure diagram of the second-order filter of the present invention.

Fig. 3 is a simulation diagram of the smoothing filtering effect of the second-order filter of the present invention.

Fig. 4 is a schematic structural diagram of the detection system of the present invention.

Detailed ways

In order to make the technical means, creative features, goals and effects achieved by the present invention easy to understand, the present invention will be further described below in conjunction with specific illustrations.

Referring to Fig. 1, what provided in the figure is a kind of automobile anti-lock braking state detection method for electric vehicle, comprises the following steps:

Step 1, collect the original speed of the motor of the electric vehicle, and calculate and process the collected original speed of the motor to generate an original speed signal V ₁ of the motor;

In step 2, a second-order filter is used to smooth and filter the generated original motor speed signal V ₁ to generate a motor speed smoothed and filtered signal V ₂ .

Among them, referring to Figure 2 and Figure 3, the transfer function of the second-order filter is:

Wherein, the value range of a is 0.7-1, the value range of b is 5.5-6.6, the value range of c is 1.5-2.5, and the value range of d is 4.5-5. Preferably, the values of a, b, c, and d in the transfer function of the second-order filter are 1, 6, 2, and 5, respectively.

Step 3: Calculate the difference ΔV=V ₁ −V ₂ between the original motor speed signal V ₁ and the motor speed smoothing filter signal V ₂ , and use the difference ΔV as the motor speed fluctuation value.

Step 4: output the motor speed fluctuation value at a certain interval T, and compare the motor speed fluctuation value output each time with the set threshold M, if the motor speed fluctuation values of multiple consecutive interval periods X are greater than the set threshold M, it is determined that the electric vehicle enters into a locked state. Wherein, the threshold M is set to be 100 rpm to 200 rpm. The interval time T for outputting the motor speed fluctuation value is 0.5ms˜1.5ms, preferably 1ms. The number of consecutive intervals is 15-25, preferably 20.

In step 5, the motor controller of the electric vehicle performs anti-lock braking control and exits braking energy recovery control at the same time.

Referring to FIG. 4 , a detection system for realizing the detection method of the anti-lock braking state of an electric vehicle includes a motor speed sensor 100 and a motor main controller 200 .

The motor speed sensor 100 is installed in the electric motor of the electric vehicle, and it rotates with the electric motor to collect the original motor speed of the electric motor, and convert the collected original speed of the motor into an electric motor speed signal for output.

The main motor controller 200 includes a motor speed calculation module 210 , a motor speed smoothing filter module 220 , a locked state judging module 230 and a motor control module 240 .

The motor speed calculation module 210 has a motor speed signal input end and a motor speed signal output end, and the motor speed signal input end of the motor speed calculation module 210 is connected to the signal output end of the motor speed sensor 100 . The motor speed calculation module 210 is used to receive the motor speed electrical signal output by the motor speed sensor 100, and calculate and process the received motor speed electrical signal, and generate the original motor speed signal _V1 for output.

The motor speed smoothing filter module 220 has a motor speed smoothing filter input end and a motor speed smoothing filter output end. The motor speed smoothing filter input end of the motor speed smoothing filter module 220 is connected to the motor speed signal output end of the motor speed calculation module 210 . The motor speed smoothing filter module 220 is used to receive the motor original speed signal V ₁ output by the motor speed calculation module 210 , and perform smoothing and filtering processing on the received motor speed original speed signal V ₁ to generate a motor speed smoothing filter signal V ₂ for output.

The locking state judging module 230 has a motor original speed signal input end, a motor speed smoothing filter signal input end and a locking state signal output end, the motor original speed signal input end of the locking state judging module 230 and the motor speed smoothing filter The signal input terminal is respectively connected with the motor speed signal output terminal of the motor speed calculation module 210 and the motor speed smoothing filter output terminal of the motor speed smoothing filter module 220 . The locked state judging module 230 is used to receive the motor original speed signal V ₁ output by the motor speed calculation module 210 and the motor speed smoothing filter signal V ₂ output by the motor speed smoothing filter module 220, and calculate the original motor speed signal V ₁ and the motor speed The difference ΔV between smoothing and filtering signals V ₂ =V ₁ -V ₂ , and the difference ΔV is used as the motor speed fluctuation value, and then the motor speed fluctuation value is compared with the set threshold value, if the motor with multiple intervals If the rotational speed fluctuation values are greater than the set threshold, it is determined that the electric vehicle enters the locked state, and the locked state judging module 230 outputs the locked state signal through the locked state signal output terminal.

The motor control module 240 has a locked state signal output end and a motor control signal output end, the locked state signal output end of the motor control module 240 is connected with the locked state signal output end of the locked state judging module 230, and its motor control The signal output end is connected with the electric motor of the electric vehicle. After the motor control module 240 receives the locked state signal output by the locked state judging module, it performs anti-lock braking control on the electric motor of the electric vehicle, and exits the braking energy recovery control at the same time.

The basic principles and main features of the present invention and the advantages of the present invention have been shown and described above. Those skilled in the industry should understand that the present invention is not limited by the above-mentioned embodiments. What are described in the above-mentioned embodiments and the description only illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also have Variations and improvements are possible, which fall within the scope of the claimed invention. The protection scope of the present invention is defined by the appended claims and their equivalents.

Claims (8)

1. An anti-lock state detection method for an electric automobile is characterized by comprising the following steps:

collecting the original rotating speed of the motor of the electric automobile, calculating and processing the collected original rotating speed of the motor to generate an original rotating speed signal V of the motor ₁ ；

For the generated motor original rotating speed signal V ₁ Smoothing filter processing is carried out to generate a motor rotating speed smoothing filter signal V ₂ ；

Calculating an original rotating speed signal V of the motor ₁ And motor rotation speed smoothing filter signal V ₂ The difference between Δv=v ₁ -V ₂ Taking the difference value DeltaV as a motor rotation speed fluctuation value;

outputting a motor rotation speed fluctuation value every time for a certain time T, comparing the motor rotation speed fluctuation value output every time with a set threshold M, and judging that the electric automobile enters a locking state if the motor rotation speed fluctuation values of a plurality of continuous interval periods X are all larger than the set threshold M, wherein a motor controller of the electric automobile performs anti-lock braking control and simultaneously exits braking energy recovery control.

2. The method for detecting the anti-lock state of an electric automobile according to claim 1, wherein a second order filter is used for generating an original rotation speed signal V of the motor ₁ Smoothing filter processing is performed.

3. The method for detecting the anti-lock state of an automobile for an electric automobile according to claim 2, wherein the transfer function of the second order filter is:

wherein, the value range of a is 0.7-1, the value range of b is 5.5-6.6, the value range of c is 1.5-2.5, and the value range of d is 4.5-5.

4. The method for detecting the anti-lock state of an electric automobile according to claim 3, wherein the transfer function of the second order filter has values of a, b, c, d of 1, 6, 2 and 5, respectively.

5. The method for detecting an anti-lock state of an electric automobile according to claim 1, wherein the set threshold M is 100rpm to 200rpm.

6. The method for detecting the anti-lock state of an electric automobile according to claim 1, wherein the interval time T of the motor rotation speed fluctuation value output is 0.5ms to 1.5ms.

7. The method for detecting the anti-lock state of an electric automobile according to claim 1, wherein the number of consecutive intervals is 15 to 25.

8. A detection system for realizing the method for detecting an anti-lock state of an automobile for an electric automobile according to any one of claims 1 to 7, comprising:

the motor rotating speed sensor is arranged in an electric motor of the electric automobile and used for collecting the original rotating speed of the motor, and the collected original rotating speed of the motor is converted into a motor rotating speed electric signal by the motor rotating speed sensor to be output;

the motor main controller comprises a motor rotating speed calculation module, a motor rotating speed smoothing filter module, a locking state judgment module and a motor control module;

the motor rotating speed calculating module is provided with a motor rotating speed signal input end and a motor rotating speed signal output end, the motor rotating speed signal input end of the motor rotating speed calculating module is connected with the signal output end of the motor rotating speed sensor and is used for receiving the motor rotating speed electric signal output by the motor rotating speed sensor, calculating and processing the received motor rotating speed electric signal and generating a motor original rotating speed signal V ₁ Outputting;

the motor rotating speed smoothing filter module is provided with a motor rotating speed smoothing filter input end and a motor rotating speed smoothing filter output end, wherein the motor rotating speed smoothing filter input end of the motor rotating speed smoothing filter module is connected with the motor rotating speed signal output end of the motor rotating speed calculating module and is used for receiving the motor original rotation output by the motor rotating speed calculating moduleSpeed signal V ₁ And receives the original rotating speed signal V of the motor ₁ Smoothing filter processing is carried out to generate a motor rotating speed smoothing filter signal V ₂ Outputting;

the locking state judging module is provided with a motor original rotating speed signal input end, a motor rotating speed smooth filtering signal input end and a locking state signal output end, wherein the motor original rotating speed signal input end and the motor rotating speed smooth filtering signal input end of the locking state judging module are respectively connected with the motor rotating speed signal output end of the motor rotating speed calculating module and the motor rotating speed smooth filtering output end of the motor rotating speed smooth filtering module, and are used for receiving a motor original rotating speed signal V output by the motor rotating speed calculating module ₁ And a motor rotation speed smoothing filter signal V output by the motor rotation speed smoothing filter module ₂ And calculates the original rotating speed signal V of the motor ₁ And motor rotation speed smoothing filter signal V ₂ The difference between Δv=v ₁ -V ₂ The difference value DeltaV is used as a motor rotation speed fluctuation value, the motor rotation speed fluctuation value is compared with a set threshold value, if the motor rotation speed fluctuation values of a plurality of continuous interval periods are all larger than the set threshold value, the electric automobile is judged to enter a locking state, and the locking state judgment module outputs a locking state signal through the locking state signal output end;

the motor control module is provided with a locking state signal output end and a motor control signal output end, the locking state signal output end of the motor control module is connected with the locking state signal output end of the locking state judging module, the motor control signal output end of the motor control module is connected with an electric motor of the electric automobile, and the motor control module receives the locking state signal output by the locking state judging module and then performs anti-lock braking control on the electric motor of the electric automobile and simultaneously exits braking energy recovery control.